C H A P T E R 4 0
Drugs affecting the female reproductive system
613
Contraindications and cautions
Contraindications and cautions for progestogens are
similar to those for oestrogens. Progestogens are also
contraindicated in the presence of pelvic inflammatory
disease (PID), sexually transmitted infections, endo-
metriosis or pelvic surgery
because of the effects of
progestogens on the vasculature of the uterus.
Dros-
pirenone is contraindicated in people who are at risk
of hyperkalaemia due to renal disorders, liver disease,
adrenal dysfunction or the use of other drugs that can
affect potassium levels
because of its antimineralocorti-
coid effects and the risk of hyperkalaemia.
Progestogens should be used with caution in people
with epilepsy, migraine headaches, asthma or cardiac or
renal dysfunction
because of the potential exacerbation
of these conditions.
Adverse effects
Adverse effects associated with progestogens vary with
the administration route used. Systemic effects are very
similar to the adverse effects of oestrogen. Dermal patch
contraceptives are associated with the same systemic
effects, as well as local skin irritation. Vaginal gel use
is associated with headache, nervousness, constipa-
tion, breast enlargement and perineal pain. Intrauterine
systems are associated with abdominal pain, endome-
triosis, abortion, PID and expulsion of the intrauterine
device. Vaginal use is associated with local irritation
and swelling. Drospirenone, used in combination con-
traceptives, has anti-mineralocorticoid activity and can
block aldosterone, leading to increased potassium levels.
Clinically important drug–drug interactions
Interaction with barbiturates, carbamazepine, pheny-
toin, griseofulvin, penicillins, tetracyclines or rifampicin
may reduce the effectiveness of progestogens. People
using any of these drugs should use another method of
contraception if birth control is needed. St John’s wort
can affect the metabolism of progestogens and can make
progestogen-containing contraceptives less effective.
This combination should be discouraged.
The current recommendation of the US Preventative
ServicesTask Force is that women should feel comfortable
taking HRT to reduce the symptoms of menopause for
short-term therapy (fewer than 5 years).The task force
summarised all of the studies and noted that long-term
use of HRT provides a decreased risk of osteoporosis and
related fractures, possibly a reduced risk of dementia and
a reduction in risk of colon cancer.The negative aspects
of this therapy include a definite but small increased risk
for heart disease, stroke and breast cancer.The harms of
long-term use outweigh the benefits for most women.The
benefits of short-term use, however, must be considered
if a woman is having a difficult time getting through
menopause (US Preventative ServicesTask Force, 2002).
Critics of the study also point out that the women in the
study were much older than most early postmenopausal
groups who could benefit from HRT; they concluded that
more research is needed on this issue (Neves-e-Castro,
2003). Follow-up research using this study has found no
correlation between use of HRT and the prevention of
Alzheimer’s disease: no drop in bone fractures in women
using HRT.
The evidence (continued)
BOX 40.4
black cohosh:
40 mg/day active ingredient, should
not be used for longer than 60 days; monitor for
dizziness, nausea, vomiting, visual disturbances;
contains alcohol—do not combine with disulfiram,
metronidazole.
borage:
90–500 mg/day PO in soft gel capsules, not for
long-term use; use caution with seizure disorders or
liver impairment.
chaste tree:
150–325 mg PO once or twice daily; may
cause increased blood pressure—avoid use with
antihypertensives or beta-blockers; may cause rash
and itching.
clary:
8 drops (gtt) in 30 mL of water daily as an atomiser
or dissolved in bath water; may cause sedation—avoid
use with alcohol; not for internal use.
devil’s claw:
1.5–6 g/day PO depending on preparation;
increases stomach acid and may interfere with many
prescription drugs; use with caution.
dong quai:
500 mg/day PO; causes photosensitivity—
avoid exposure to the sun; do not use with warfarin—
increased bleeding can occur.
false unicorn root:
1–2 mL PO three times a day; do not
use with oestrogen or progestins—may alter uterine
effects.
red clover:
4 g PO three times a day as tea; 30–60 gtt PO
three times a day of liquid extract; do not use with
heparin or warfarin because of increased bleeding
effects; do not combine with hormone replacement
therapy because of risk of increased oestrogenic
effects.
soy:
25 g/day PO; do not use with calcium, iron or
zinc products; may decrease effects of oestrogen,
raloxifene, tamoxifen—alert healthcare provider if
combining these drugs.
wild yam:
1–6 g/day PO; contains progesterone—do not
use with hormone replacement therapy; may cause
increased blood glucose and other toxic effects; do
not combine with disulfiram or metronidazole—severe
reaction may occur.
Herbal and alternative therapies
BOX 40.5
